Changes of Divalent Cation Absorption in Root, Shoot, and Leaf of Gerbera Affected by Different Levels of Ca and Humic Acid

The problem of decreasing Gerbera (Gerbera jamesoni L.) quality as a consequence of disturbance in the uptake of mineral nutrients is a major problem، especially in winter and when the greenhouse condition are not appropriate. One of the important problems of gerbera growers is bent neck and low quality flowers that may even occur one day post-harvest. To assess the factors affecting the process and controlling it، an experiment was conducted in Zhejiang University، Hangzhou، China. The effect of 3 concentrations of humic acid (100، 500، and 1000 mg/l and the control) with two levels of calcium (3. 5 and 7 meq/l) was studied on gerbera cv. Malibu The results showed that increasing only the Ca level in nutrient solution did not change the Ca concentration of leaf and root while addition of 500 mg/l humic acid (HA) increased Ca concentration. Also، HA increased nutrient absorption، especially Ca، Mg and Zn. Mg concentration of leaves decreased in 7meq Ca/l treatment without HA and application of HA increased it. Mg concentration of root increased in 7meq Ca/l and 1000 mg/l HA and 500 mg/l HA، respectively. The highest Ca concentration of leaf was in 7meq Ca/l and 500mg/l HA. The highest Zn concentration of root and shoot was in 7meq Ca and 500 mg/l HA. Generally، humic acid، with chelating characteristic، improved Ca absorption as well as Mg and Zn، which have antagonistic effect with Ca. Therefore، using 500 mg/l HA in production of gerbera in greenhouses is recommended